The present invention relates to footwear, and more particularly to a sole assembly for footwear.
There are a variety of footwear constructed for efficient function in different activities. Many footwear are designed to provide a high level of stable support, coupled with impact attenuation upon engagement with an underfoot surface, such as the ground. Much of the support and impact protection afforded by footwear is attributable to the configuration of the sole. The sole protects the foot by dispersing significant forces caused by running, jumping, training and even walking. The sole also provides cushioning that absorbs impact and protects the wearer's appendages, such as their feet, ankles and knees, from the stress associated with strenuous and even day-to-day activities. At the same time, the sole plays a role in helping support the foot in its proper shape to prevent a wearer's feet and legs from becoming fatigued over time.
The objectives of providing adequate impact attenuation and providing support often compete with one another. A highly cushioned sole, designed to compress and efficiently absorb significant impact forces, may not provide sufficient foot support, and this may lead to premature foot fatigue. Such a cushioned sole also might not allow a proper distribution of forces along the bottom of the foot during a gait cycle, which can lead to an erratic torsional, lateral, or lengthwise twisting or rotation of the foot, which can be deleterious to the gait of the wearer. On the other hand, an overly firm sole, designed to provide support and stabilize the foot during the gait cycle, may feel uncomfortable, and may not provide the cushioning needed to protect the wearer against potential damage or injury associated with repeated ground impact. Furthermore, such a sole might be so rigid that it impairs the foot from following its natural flexing and bending form through the gait cycle, which can also alter the wearer's gait in such a way so as to reduce efficiency and energy return.
Accordingly, there is a reason for improving developing footwear sole constructions that provide an appropriate balance between impact attenuation, durability, and support.